An increasing number of marine microorganisms are being studied as a potential source of novel metabolites with unique biotherapeutic activity. Current methods involve isolating marine microorganisms from environmental samples, obtaining cell extracts or culture supernatants, using cellular or biochemical assays to analyze the extracts or supernatants for secreted metabolites, and isolating high secretors by serial dilutions. These methods are time consuming and labor intensive. In Phase I research, single cell gel microdrop (GMD) encapsulation technology will be combined with a unique receptor-ligand screening format and fluorescence activated cell sorting (FACS) to permit rapid isolation of individual marine microorganisms based on secretory activity, which is currently not possible. Using FACS, sub-populations of secretors as small as 1 percent can be rapidly isolated. Phase I research will develop the GMD assay using endotoxin-secreting E. coli and validate the assay using well characterized marine microorganism isolates which secrete endotoxin. Phase I research will also evaluate use of high-speed sorters to increase screening throughput. The GMD assay will help to streamline the search for potential new drug candidates derived from natural marine environments. PROPOSED COMMERCIAL APPLICATION: The proposed assay will facilitate drug discovery by permitting direct isolation of marine microorganisms based on secretory activity.